Bag stripping means for an automatic bag making device

ABSTRACT

The bag stripping device is provided with an endless continuously moving stripping band whose upper horizontal stringer is urged by a pair of rollers on a rocker against the lower horizontal side wall of a bag which is formed by folding and gluing a blank on a horizontally disposed mandrel. The mandrel is provided with a pivotally mounted horizontal jaw adapted to loosely engage the inner face of said horizontal wall of the bag, and two rollers within said mandrel are oppositely disposed to said above mentioned pair of rollers for engaging said horizontal side wall of the bag and permit a stripping of the bag from the mandrel by the lengthwise movement of said stripping band. After the bag has been stripped from the mandrel the bag is engaged between an endless upper bag engaging member and said stripping band and is tilted at the end of said stripping band and transferred to a conveyor which moves the bag in an upright position to a bag filling device.

United States Patent 91 Auckenthaler BAG STRIPPING MEANS FOR AN AUTOMATIC BAG MAKING DEVICE Inventor: Robert Auckenthaler, Schaffhausen,

Switzerland Schweizerische Industrie-Gesellschaft, Neuhausen am Rheinfall, Switzerland Filed: Jan. 3, 1972 Appl. No.: 214,792

Assignee:

Foreign Application Priority Data Jan. 6, 1971 Switzerland l37/7l References Cited UNITED STATES PATENTS 10/1961 Phin 93/59 ES X 9/1970 Kuhnle 93/12 R 7/1902 Kellner 93/12 R Oct. 16, 1973 Primary Examiner-Andrew R. Juhasz Assistant Examiner-James F. Coan Attorney-Benjamin H. Sherman et al.

[5 7] ABSTRACT The bag stripping device is provided with an endless continuously moving stripping band whose upper horizontal stringer is urged by a pair of rollers on a rocker against the lower horizontal side wall of a bag which is formed by folding and gluing a blank on a horizontally disposed mandrel. The mandrel is provided with a pivotally mounted horizontal jaw adapted to loosely engage the inner face of said horizontal wall of the bag, and two rollers within said mandrel are oppositely disposed to said above mentioned pair of rollers for engaging said horizontal side wall of the bag and permit a stripping of the bag from the mandrel by the lengthwise movement of said stripping band. After the bag has been stripped from the mandrel the bag is engaged between an endless upper bag engaging member and said stripping band and is tilted at the end of said stripping band and transferred to a conveyor which moves the bag in an upright position to a bag filling device.

5 Claims, 3 Drawing Figures 13 Z I XV X il 3 Y 25 I ,l25 38 5 2'1 23 6\ g 9 232 iq l l 5 1 Q @J 39 28 2, 1 m 11\ I 4 is I r 0 2 12 10 I 2 i1 18 g I E"l ,6 7 *1 PATENTEB OCT 16 I973 SHEET 10F 2 BAG STRIPPING MEANS FOR AN AUTOMATIC BAG MAKING DEVICE In known devices of this type the bag stripping device I is provided with a slidable member which is caused to move back and forth by a cam disc, and this slidable member is equipped with a stripping element which engages the bag and withdraws it from the mandrel. The capacity of such a device is, among other things, limited by the inertia forces which are generated during the back-and-forth movement of the slidable member and these forces become excessive with increasing operating speed so that difficulties occur, particularly during the transfer of the stripped bag from. the slidable member to additional conveying members.

It is the object of the invention to provide a stripping device with at least one continuously driven endless stripping member which is equipped with a portion movable in the longitudinal direction of the mandrel and past the same, whereby this portion of-the stripping member is urged by a pressure device against a side wall of the bag on the mandrelain order toengage the bag with friction and to strip it from the mandrelJSince this portion of the endlessstripping member, for instancean endless band,'moves andalways in the same direction and also moves the bag in this direction, and since the pressure device practically has a very small mass compared with the previously employed reciprocable slidable member, the above mentioned disadvantages of the known stripping devices are eliminated and this results in actual practice in an increase in-production of bags in the order of about 50 percent.

The drawing illustrates by way of example an embodiment of the device of the invention.

FIG. 1a illustrates in alongitudinal section the left hand portion of a stripping device of a'bag producing machine substantially along the broken II of FIG. 2.

FIG. lb illustrates the right hand end of the stripping device also taken along the broken line l-I.of FIG. 2.

FIG. 2 illustrates a cross section of the stripping device substantially along the broken line II-II of FIG. la.

Referring to the drawing, the device for the making of bags is provided with a mandrel 1 which, after a stepwise passage through a plurality of stations, reaches the last station illustrated in FIG. 1a of the bag producing cycle. In this FIG. 1a the completed bag '2, which has been formed on the. mandrel l, is to be stripped from the latter; The mandrel l in FIG. la consists principally of a horizontally disposed mandrel body 3 and a horizontal mandrel jaw 4, which with one of its ends at 5 is pivotally mounted on the body 3. A vertical pressure spring 6 surrounds a vertical pin 7 attached to the body 3 and has the tendency to move the jaw 4 toward an opening position, namely, downwardly so that an abutment shoulder 8 in a countersunk bore engages a head 9 provided on the lower end of the pin 7. In FIG. la the shoulder 8 does not engage the head 9 because an abutment roller 10 mounted on a vertical pin 11 attached to the jaw 4 is being engaged by a control cam 12 and therefore the jaw 4 has been moved counterclockwise against the force of the spring 6 in the opposite closure direction.

In the rest position of the jaw 4, which is the position in which the shoulder 8 engages the head 9, and which occurs in the preceding stations and on the way be tween the same, the mandrel 1 has in cross section a rectangular profile as shown in FIG. 2. In the preceding stations the bag 2 will be formed in known manner from a blank of any desired type, for instance, it may be made of paper, metal, or plastic. This blank is successively folded around the mandrel 1 to form firstly the side walls 13 and then the bottom 14 of the bag 2. The bag 2 remains open opposite the bottom 14 and has a filling opening 15. The mandrel 1 may, for instance, be one of a plurality of other mandrels of the same type which radially project outwardly from the hub of a mandrel wheel which rotates about a vertical axis and is located to the left hand side of FIG. la so that by a stepwise rotation the mandrels one after the other will be moved into the different stations. In the last station the blank is not only folded, but may also in the folded condition be glued or welded to form a fixed shape. The mandrels may, however, also be moved in cycle by means of an endless conveyor chain, one after the other, from one station to the next one.

The invention provides a device 16 for stripping the bags 2 from a horizontally disposed mandrel. This device 16 is equipped with an endless stripping band 17 threaded over two horizontal and substantially horizontally spaced rollers 18 and 19. One of these rollers, for instance, the roller 19, (FIG. lb) is continuously driven clockwise as indicated by the arrow 20. The upper stringer 17 of the endless stripping band 17 moves along the horizontal legs 21 and 22 of two equal sided angle irons 21, 22. In order to produce between the lower side wall 13 of the bag 2 and the upper stringer 17 of the band 17 a high friction the invention provides two pairs of oppositely disposed pressure rollers 23 and 24. The two upper rollers 23 are rotatably supported on two supports 25 arranged within the hollow space 26 of the mandrel body 3 and are attached to the latter. These two rollers 23 are arranged in the longitudinal center plane of the mandrel 1 and project into two openings 27 provided in the horizontally disposed jaw 4. In the rest position of the horizontally disposed jaw 4 its lower outer surface 28 is tangentially disposed to the lower portion of the rollers 23 while in the illustrated stripping position the rollers 23 project beyond this outer surface 28.

The two other lower pressure rollers 24 are rotatably mounted on the opposite ends of a horizontally arranged rocker 29, the center of which is pivotally mounted by a horizontal pin 30 to a fork 31. The fork 31 is arranged at the free end of a substantially horizontally extending arm 32 which is pivotally supported by a horizontal pin 33 secured to the vertical leg 21 of the angle iron 21. This pin 33 is, however, not illustrated in FIG. 2 for the sake of clearness. At the free end of the arm 32 which carries the fork 31 is also attached another pin 34 to which is pivotally mounted the upper end of a vertical operating rod 35 which is movable back and forth in vertical direction as indicated by the double arrow 36. The rollers 24 extend through marginal recesses 37 arranged in the horizontal legs 21, and 22, of the angle irons 21 and 22. The upper faces of the angle iron legs are tangential with respect to the rollers 24 prior to the raising of the operating rod 35 or may also be disposed somewhat above the same. When the vertical rod 35 is raised then the rollers 24 urge the upper stringer 17 of the stripping band 17 toward the rollers 23 and against the lower horizontal sidewall 13 of the bag 2 so that the bag 2 will be engaged by the upper stringer 17 to move with the same so that the bag 2 is stripped from the mandrel 1.

In order to avoid that between the vertically disposed bottom 14 of the bag 2 and the adjacent end wall 38 of the mandrel l, in spite of the small space 39 between the body 3 and the jaw 4, a low pressure may be produced during the stripping operation, the mandrel body 3 may be provided in its end wall 38 with an aperture 40. In the event that the operating speed of the stripping device is very high it is advisable to provide a not illustrated compressed air line which extends through the shaft of the mandrel wheel and to the aperture 40 so that in the instant of the stripping procedure a stream of compressed air may be blown against the bottom 14 so that the stripping of the bag 2 is facilitated or accelerated. It is obvious that after the stripping of the bag 2, the rod 35 is again lowered before the next mandrel 1 moves into the stripping station.

For the purpose of holding the bag 2 on the upper stringer 17, the invention provides an endless rubber cord 41 which is guided over rollers 42 to 49 as shown, particularly in FIG. 1b. One of these rollers, for instance the roller 42 (FIG. la) is continuously driven in the direction of the arrow 46 so that the cord 41 is moving in the same direction and with the same speed as the endless stripper band 17. A section 41 of the cord 1 moves in spaced relation parallel above the stringer 17 and in the same direction as the same and at such a distance from the same which is somewhat less than the corresponding transverse dimension of the bag 2 so that the latter with a small force is elastically urged by the cord 41 against the stringer 17 The two rollers 46 and 47 are rotatably mounted at the opposite ends of a rocker 50, the center of which is rotatably mounted on horizontal pin 51 which is in turn pivotally mounted in a stationary bearing of the machine frame 6. The rocker 50 is pivotally moved back and forth about the pin 51 by a not illustrated means, for instance, by a cam disc, in a manner indicated by the double arrow 52.

In the rest position of the rocker 50, as shown in FIG. 1b, the section 41 of the cord 41 between the rollers 46 and 47 is disposed in alignment with the horizontal section 41 so that the stripped bag at the end of the stringer 17 moves into the position 2 indicated in dash and dotted lines in FIG. lb. At this instant the rocker 50 is tilted into the position 50, illustrated in dash and dotted lines, so that the section 41, comes into position 41 and the bag performs an angular movement a of approximately 45 beyond the discharge end of the stringer 17,.

The bag is hereby transferred to a receiving seat 53 having an angle of 90 and mounted on a pivoted erection arm 54. The rollers 45 and 48 are so arranged that the length of the cord 41, during tilting of the rocker 50 does practically not change in its length for all practical purposes. Minor differences in the length are compensated for by the elasticity of the rubber cord 41.

The erection arm 54 is pivotally attached to a horizontally disposed stationary shaft 55 so that the arm 54 may be pivoted about an angle of minus 0:; namely about 45 clockwise, and will come into the position 54' illustrated in dash and dotted lines.

The bag is now disposed in a vertical position and may be conveyed by a not illustrated conveyor in this upright position to a filling station. For an intended possible filling of the bag while on the arm 54, the time interval between the arrival of two successively filling bags into the position 2 is for all practical purposes too short if the advantage of the device, namely a high production of, for instance bags per minute, is to be realized.

It should be noted that in place of a single endless stripping band 17, one may also use a number of parallel narrow stripping bands or cords. Furthermore, in place of a single rubber cord 41, one may also employ a band or a plurality of parallel bands or cords. Furthermore, in place of the rollers 23 and 24 one may also employ slidable bodies.

What I claim is:

1. Bag stripping means for an automatic bag making device provided with a plurality of mandrels which successively move through several operating stations and on whose last station the bag blanks are folded and cemented, said stripping means comprising at least one continuously horizontally moving endless stripping member moving in longitudinal direction of the mandrel which presents a bag for stripping, pressure means for urging said stripping member against a horizontal wall of the bag on said mandrel for frictionally engaging said wall and horizontally stripping said bag from said mandrel, a horizontal jaw pivotally mounted with one of its ends to said mandrel and extending into engagement with the inner face of the wall of said bag whose outer face is engaged by said stripping member, spring means for urging said jaw toward engagement with said wall, a first roller means in said mandrel and extending through apertures in said jaw and in engagement with said wall of said bag, and other roller means opposite said first roller means and adapted to engage said stripping member and urging it against said outer face of said bag on said mandrel.

2. Bag stripping means according to claim 1, including a rocker mounted pivotally with its center position to the upper end of a vertically reciprocable operating rod, said other rollers being rotatably mounted at the ends of said rocker.

3. Bag stripping means for an automatic bag making device provided with a plurality of mandrels which successively move through several operating stations and on whose last station the bag blanks are folded and cemented, said stripping means comprising at least one continuously horizontally moving endless stripping member moving in longitudinal direction of the mandrel which presents a bag for stripping, and pressure means for urging said stripping member against a horizontal wall of the bag on said mandrel for frictionally engaging said wall and horizontally stripping said bag from said mandrel, said mandrel being provided with an end wall engaging the inner face of the bottom wall of said bag, said end wall being provided with an aperture for the introduction of compressed air to assist in the stripping of said bag from said mandrel.

4. Bag stripping means for an automatic bag making device provided with a plurality of mandrels which successively move through several operating stations and on whose last station the bag blanks are folded and cemeneted, said stripping means comprising at least one continuously horizontally moving endless stripping member moving in longitudinal direction of the mandrel which presents a bag for stripping, pressure means for urging said stripping member against a horizontal wall of the bag on said mandrel for frictionally engaging said wall and horizontally stripping said bag from said mandrel, an endless bag engaging member arranged in part in parallel spaced relation above said endless stripping member and moving in the same direction as the latter, so that said bag after being stripped from said mandrel is engaged by both said bag engaging member and said stripping member and moved away from said mandrel, said endless bag engaging member being provided adjacent the one end of said endless stripping member with a section extending between two guide rollers on a rocker and normally in horizontal alignment with the preceding section of said bag engaging member, means for tilting said rocker so as to discharge said bag from said endless stripping member, and means for receiving said tilted bag and moving it to an upright position.

5. Bag stripping means for an automatic bag making device provided with a plurality of mandrels which successively move through several operating stations and on whose last station the bag blanks are folded and cemented, said stripping means comprising at least one continuously horizontally moving endless stripping member moving in longitudinal direction of the mandrel which presents a bag for stripping, pressure means for urging said stripping member against a horizontal wall of the bag on said mandrel for frictionally engaging said wall and horizontally stripping said bag from said mandrel, an endless bag engaging member arranged in part in parallel spaced relation above said endless stripping member and moving in the same direction as the latter, so that said bag after being stripped from said mandrel is engaged by both said bag engaging member and said stripping member and moved away from said mandrel, said endless bag engaging member being provided adjacent the one end of said endless stripping member with a section extending between two guide rollers on a rocker and normally in horizontal alinement with the preceding section of said bag engaging member, means for tilting said rocker so as to discharge said bag from said endless stripping member, and means for receiving said tilted bag and moving it to an upright position, said endless bag engaging member comprising an elastic cord whose length remains substantially unchanged when said one section of the same is tilted with said rocker. 

1. Bag stripping means for an automatic bag making device provided with a plurality of mandrels which successively move through several operating stations and on whose last station the bag blanks are folded and cemented, said stripping means comprising at least one continuously horizontally moving endless stripping member moving in longitudinal direction of the mandrel which presents a bag for stripping, pressure means for urging said stripping member against a horizontal wall of the bag on said mandrel for frictionally engaging said wall and horizontally stripping said bag from said mandrel, a horizontal jaw pivotally mounted with one of its ends to said mandrel and extending into engagement with the inner face of the wall of said bag whose outer face is engaged by said stripping member, spring means for urging said jaw toward engagement with said wall, a first roller means in said mandrel and extending through apertures in said jaw and in engagement with said wall of said bag, and other roller means opposite said first roller means and adapted to engage said stripping member and urging it against said outer face of said bag on said mandrel.
 2. Bag stripping means according to claim 1, including a rocker mounted pivotally with its center position to the upper end of a vertically reciprocable operating rod, said other rollers being rotatably mounted at the ends of said rocker.
 3. Bag stripping means for an automatic bag making device provided with a plurality of mandrels which successively move through several operating stations and on whose last station the bag blanks are folded and cemented, said stripping means comprising at least one continuously horizontally moving endless stripping member moving in longitudinal direction of the mandrel which presents a bag for stripping, and pressure means for urging said stripping member against a horizontal wall of the bag on said mandrel for frictionally engaging said wall and horizontally stripping said bag from said mandrel, said mandrel being provided with an end wall engaging the inner face of the bottom wall of said bag, said end wall being provided with an aperture for the introduction of compressed air to assist in the stripping of said bag from said mandrel.
 4. Bag stripping means for an automatic bag making device provided with a plurality of mandrels which successively move through several operating stations and on whose last station the bag blanks are folded and cemeneted, said stripping means comprising at least one continuously horizontally moving endless stripping member moving in longitudinal direction of the mandrel which presents a bag for stripping, pressure means for urging said stripping member against a horizontal wall of the bag on said mandrel for frictionally engaging said wall and horizontally stripping said bag from said mandrel, an endless bag engaging member arranged in part in parallel spaced relation above said endless stripping member and moving in the same direction as the latter, so that said bag after being stripped from said mandrel is engaged by both said bag engaging member and said stripping member and moved away from said mandrel, said endless bag engaging member being provided adjacent the one end of said endless stripping member with a section extending between two guide rollers on a rocker and normally in horizontal alignment with the preceding section of said bag engaging member, means for tilting said rocker so as to discharge said bag from said endless stripping member, and means for receiving said tilted bag and moving it to an upright position.
 5. Bag stripping means for an automatic bag making device provided with a plurality of mandrels which successively move through several operating stations and on whose last station the bag blanks are folded and cemented, said stripping means comprising at least one continuously horizontally moving endless stripping member moving in longitudinal direction of the mandrel which presents a bag for stripping, pressure means for urging said stripping member against a horizontal wall of the bag on said mandrel for frictionally engaging said wall and horizontally stripping said bag from said mandrel, an endless bag engaging member arranged in part in parallel spaced relation above said endless stripping member and moving in the same direction as the latter, so that said bag after being stripped from said mandrel is engaged by both said bag engaging member and said stripping member and moved away from said mandrel, said endless bag engaging member being provided adjacent the one end of said endless stripping member with a section extending between two guide rollers on a rocker and normally in horizontal alinement with the preceding section of said bag engaging member, means for tilting said rocker so as to discharge said bag from said endless stripping member, and means for receiving said tilted bag and moving it to an upright position, said endless bag engaging member comprising an elastic cord whose length remains substantially unchanged when said one section of the same is tilted with said rocker. 